A novel geometrical analysis of the arterial pulse based on the golden ratio φ (PHI): Association with heart rate variability - Papaioannou, T.G.; Gialafos, E.; Vavuranakis, M.; Vrachatis, D.; Soulis, D.; Siasos, G.; Kyrlagkitsis, S.; Stefanadis, C.; Tousoulis, D. (Archives of the Balkan Medical Union, 2018)